Field of the Invention
The present invention relates to an image forming apparatus including a high-voltage generation circuit.
Description of the Related Art
In an image forming apparatus of an electrophotographic type, a voltage (high voltage) that is higher than a voltage of a commercial power supply is applied to charging rollers, developing rollers, and transfer rollers. A high voltage generated by a high-voltage generation circuit may be used for purposes other than image formation. Japanese Patent Laid-Open No. 2002-333812 suggests a method of detecting abnormal attachment of photosensitive drums in accordance with a current that flows in charging rollers as a result of applying a high voltage to the charging rollers.
Incidentally, in an image forming apparatus, a control board on which a control circuit is mounted and a high-voltage board on which a high-voltage generation circuit is mounted are electrically connected via a cable. It is thus necessary to detect the state of electric connection between the control board and the high-voltage board. Japanese Patent Laid-Open No. 2002-178490 suggests the following technique: connectors for boards include a plurality of terminals that are lined up thereinside, two terminals located at both ends in each connector are short-circuited when mounting the boards, and a connection detection circuit judges that a normal state has been achieved when the short-circuited state is detected via a cable connected to the connectors.
However, according to Japanese Patent Laid-Open No. 2002-178490, it is necessary to provide the connection detection circuit on at least one of the two boards that are connected via the cable. Furthermore, among a plurality of signal lines constituting the cable, two signal lines located at both ends are used only for the connection detection, and cannot be used for other purposes. Similarly, the two terminals inside each connector cannot be used for other purposes. Such restrictions are disadvantageous in terms of installation space and manufacturing cost.